[horde] Bottleneck ? CPU or HDisk IO or RAM

[Rob MacGregor]

On Tue, Feb 3, 2009 at 11:07, Linux Advocate <linuxhousedn at yahoo.com> wrote:
>>
>> Configured how - is that a 6 disk RAID5 array or a 6 disk RAID10 array
>> (ie a stripe of 3 RAID1 pairs)?  Is it hanging off a hardware RAID
>> controller (brand and model?) or as a software RAID?  What type of bus
>> is it hanging off of if it's a controller (PCI, PCI-X, PCIe etc)?
>
> perc raid controller, pci-e. a raid 5 config.

Switch to RAID-10 and if you haven't already install a battery backup
unit (BBU).  RAID-5 is relatively poor at writes (each write requires
that it reads the other disks in the array, calculate the checksum and
then write the checksum, so in a 6 disk array each logical write
generates 4 physical reads and 2 physical writes).  If you've got an
actively changing environment that may cause you major issues.

-- 
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Rob MacGregor
      Whoever fights monsters should see to it that in the process he
        doesn't become a monster.                  Friedrich Nietzsche